Automatic portable feed for drills.



E. H. CHAPMAN. AUTOMATIC PORTABLE FEED FOR DRILLS.

' APPLICATiON F|LED 5EPT.18. 1915- 'j.,f 2 30', Patented Oct. 24, 1916.

. 3 SHEETS-SHEET l- WITNESSES 6 In MET/on BY .'.I.'

ATTORNEYS n4: mwms PEIERS co.. Pnomuma. wnsuma mu. 0. c4

E. H. CHAPMAN.

AUTOMATIC PORTABLE FEED FOR DRILLS.

APPLICATION FILED SEPT. 18. 1915.

1,2,030, Patented Oct. 24,1916. I 3 SHEETS-SHEET 2.

.Z 26 so 42 WITNESSES $4 9 NVENTOR .,;.o4:z &x

ATTORNEYS E. H. CHAPMAN. AUTOMATIC PORTABLE FEED FOR DRlLLS.

APPLICATION FILED SEP T.18, 195- 22,030,

Patented (m. 24, 1916.

3 SHEETS-SHEET 3 WITNESSES ATTORNEYS FNDm-LITNO WASNINGIDN. n.'c.

AUTOMATIC PORTABLE FEED FOR DRILDS.

Application filed September 18, 1915.

To all whom it may concern Be it known that I, EDWARD H. CHAPMAN,

attachments for air and electric drills, or

drill presses of various types, in which provision is made for automatically feeding the drill into the work and for disconnecting the feed-mechanism without affecting the rotary movement of the drill, and it comprises a machine tool of the character employed where a hand-feed is necessary, and which can be adapted for use with any type of portable drills.

It is a new and useful departure from the old hand-feed type of air and electric drills, the objections to the more or less practical forms of which have been that it has not been possible to feed them at a consistently uniform speed, and that at times the drill or hit, instead of cutting, has revolved idly in the drilled hole, with the result that the cutting edges have been blunted, a large vol ume of the operating medium wasted, and the drill so choked and stalled as to necessitate its withdrawal and starting anew.

In the old practice with machines actually used, it has also resulted that when any reasonable speed has been secured, two opera-' tors have been needed, one to hold and operate the tool andthe other to lubricate it. I have, moreover, found that the number of holes drilled by different operators has varied even to the extent of fifty percentum, one man having been able to do twice the work of another, a result largely due to improper feeding of the machine.

With the object of remedying the foregoing disadvantageous conditions, I have invented a portable drill which can be accu' rately hand-fed, and which embraces and consists of the special features which are represented in the accompanying drawings, hereinafter described, and recited in the claims.

For the'purpose of illustrating my invention, I have shown in the accompanying drawings certain types and embodiments of it which are at present preferred by me because in practice. they will be found to give Specification of Letters Patent.

Serial No. 51,382.

satisfactory and reliable results. It is to be understood, however, that the various instrumentalities in which my invention is embodied can be variously arranged and organized and that my invention is not therefore limited to the precise arrangement and organization of these instrumentalities which are typified in. the constructions illustrated in the accompanying drawings and hereinafter described.

Referring to the drawings, Figure 1 represents a vertical, central, sectional elevation of a portion of a drill embodying my invention,certain of the parts being represented in broken side elevation. Fig. 2 represents, partly in section and partly in elevation, a modified form of the drill. represented in Fig. 1. Fig. 3 represents a sec tion on line g y Fig. at of a modification of the type of drill represented in Figs. 1 and 2, showing two sets of feed gears and means for engaging and disengaging them: certain parts being omitted for the sake of clearness of illustration. Fig. 4 represents in vertical, sectional, elevation, on the dotted line of Fig. 3, the typical embodiment represented in said Fig. 3, and Fig. 5 represents, on an enlarged scale, a sectional detail of the gear stem and locking pin.

Similar numerals of reference indicate corresponding parts.

Referring first to Fig. l of the drawings, 1 represents a drill casing of any usual or preferred character,and 2 and 3 its handles.

4 designates the cylindric upper or outer portion of a rotatable feed screw, the eX- ternally threaded portion of which is designated 5, the threads, which may be of a predetermined number and pitch, matching with internal threads 6 formed within a hollow drill spindle 7 extending longitudinally of the casing within a cylindric bore thereof, the upper bearing surface of which bore is designated 8, the middle 9, and the lower 10.

The feed screw at the end opposite to the drill socket is provided with a pyramidal tip or pin 11 retained by a cap 12 and provided with a ball-race 13 intermediate the end of the feed screw and the tip, the latter being adapted to engage a suitable abutment (not shown).

The form of the tip is not essential and it simply serves, when held stationary, to permit of the free rotation of the feed screw.

Patented Oct. 24, 1916; 1

ran srn'rns PATENT rmo.

The drill spindle or drill-carrying member, is rotatable within the bearing surfaces 8, 9, and 10, of the bore of the casing, and a ball-race 1i intervenes between a shoulder 15 of said spindle and the middle bearing surface 9 of the casing,

The lower end of the feed screw is formed with a pintle 16, which in the downward. or outward movement of the feed screw enters within a socket 17 formed within the drill spindle, so as to stop the outward movement of the feed screw.

The outer or lower end of the drill spin dle terminates in theusual. drill socket within which the drill bit, or other implement,

(not shown) engages.

The rotation of the drill spindle in the operation of the tool, is, in the manner common to drills operated by the agency of compressed air or other motive fluid or elec tricity, effected through the spur wheel 18, pinion 19, and shaft 20, and its rotation is transmitted to the feed screw 'by the following manually actuated supplemental controlling gearing 21 is a feed gear appropriately housed within the casing and keyed to the drill spindle 7. This feed gear meshes with an idle gear 22, freely revoluble upon. a gear stem housed in an offset 24: of the casing, and preferably in axial parallelism with the feed screw. The gear stem 23 is susceptible of vertical movement within bearings and 26 in the casing offset 2 and above is adapted to engage so as to lock the stem in a desired position.

It will be'seen from the foregoing that this locking pin 34 is a manually operated locking device to retain the gear stem 23 in an upper or a lower position, so as to mak possible the engagement or disengagement of the idle gear 22 with or from the driving gear 27, which are respectively provided with opposing clutch faces 36 and 37, which. when engaged, lock the two gears so tha they rotate together, or. when disengaged,

free them so that the driving gear 27 stops its rotation while the idle gear 22 continues freely to rotate.

38 designates what I term a "driven gear which meshes with the driving gear 27 and is conveniently provided with a hollow speed of revolution.

knurled thumb sleeve 39, which extends upwardly beyondrthe casing and encompasses both the smooth portion i and the upper threaded portion 5 of the feed screw upon which it is revoluble, so as, at will, through the intervention of the feather 4:0 hereinafter described, to make it possible manually to turn the feed screw.

The driven gear 88 and the thumb sleeve 39 are a unit, and the gear member 88 is, as explained, in constant engagement or meshed with the driving gear 27.

i0 is a feather or spline extending radially inwardly from the thumb sleeve 3%) of the driven gear 38, and sliding in a featherway ll longitudinally recessed in the exterior of the feed screw i and 5, and interior of the thumb sleeve 39, so that in the rotation of the driven gear 38, whether manually through the thumb sleeve 39 as already explained, or when the driving gear 27 is locked to the idle gear 22 through said driving gear, the feed screw will be rotated.

42 is a bearing washer and spacer encircling the upper end of the drill spindle T and separating the feed gear 21 and the driven gear 38.

Such being a descrn tion of the preferred form of my drill, its operation for feeding forward the feed screw and .drill,-assuming the parts to be in the position in Fig. 1 and the screw to be right-handed,--is as follows :The feed screw being retained against backward movement by resting its tipped cap against an abutment,the drill spindle is caused to revolve by the action of the motive fluid operating through the shaft 2(), gear 19, and spur wheel 18, and, revolv ing, transmits its motion to the feed screw through the feed gear 21, which, as

ear to the idle gear 22,assumed, in this iovement, through its clutch face 36 to be an engagement with the clutch face 37 of the driving gear 27,-through said driving ear 27, and through it to the driven gear 8, which, as explained, is in mesh with said riving gear 27, and through the feather 40 nd said driven gear 38, to the feed screw. The revolutions of the drill spindle are, therefore, the same as those of the feed screw and drill, and reduction in their relative speeds is effected by the difference in the number of teeth in the gears 38 and 27 r 21 and 22. When the reduction is made ither through the gears 38 and 27, or through the gears 21 and 22, the feed screw he gear 38 or the gear 21 will. have one or several more teeth, respectively, than the gears 27 or 22,-the relative numerical diference being calculated for the required Assuming, upon the other hand, the feed screw to be left-handed, then'the gears 27 or 22 will'have a greater s right-handed, with the result that either.

lplained, is keyed upon it, and through said number of teeth than the gears 38 or 21. Obviously, also, the feed per revolution will vary according to the number of threads per inch upon the feed screw, relatively and correspondent, of course, to the number of the internal threads of the drill spindle.

The operation of returning the drill to its original position after the hole has been bored, is as follows: Assuming the feed screw to be right-handed it is first necessary to throw out the locking pin 34 and lift the driving gear 27 fro-1n the idle gear 22, after which, through the rotation of the thumb sleeve and the driving gear, the feed screw will be manually returned to its original position; the return being accomplished, as already explained, through the instrumentality of the feather 4:0 and feather-way 41. Assuming, upon the other hand, that the feed screw is left-handed, its return to its original position can be accomplished by the power of the drill itself, by releasingthe clutching faces between the gears 22 and 27 and then manually holding against rotation the knurled thumb sleeve of the driven gear.

In practice, I prefer to employ a lefthanded screw which can be returned by the power of the instrument.

It will be obvious that by employing gears with relatively different numbers of teeth and by calculating the numbers of threads per inch of the feed screw, any desired revolution of the drill may be obtained.

Referring now to the modified construction represented in Fig. 2,the drill as an entirety is organically the same as the embodiment represented in Fig. 1 and already described, with the exception that the feed thread is out upon the drill spindle, which,

therefore, subserves the dual purpose of a drill spindle and feed screw for the drill, and not alone that of a feed screw per so. In this embodiment, in which the same numerals of reference as in Fig. 1' are used, the casing as an entirety is designated 1, and as an entirety moves up and down with reference to the drill spindle 7, the upper portion of which is the threaded portion and the lower portion the unthreaded or cylindriform surface, and which is connected with the spur wheel 18 by means of a key 43. In this embodiment, the feed gear 21, which extends downward in the form of a sleeve 44, is journaled within a bearing 45 in the casing. This sleeved-feed gear 21 meshes with an idle gear 22 within an offset 24 of the casing, and said idle gear is formed with an upper clutch face 36 to engage with a lower correspondent clutch, face 37 of the driving gear 27 substantially as in the con structlon of Flg. 1, sothat further description of the clutch faces is unnecessary. The

gear stem 23 of this pair of gears is, how-Ii ever, formed with adiametrically enlargedlaistruction'of Fig. 1, may be maintained.

' Referring now to the construction repre- &

clutch base 46, the upwardly-facingperiphwith its axis. Obviously, when the gear stem 23 is raised so as to disengage the clutchfaces 36 and 37 by elevating the driving gear 27 and causing it to cease rota-' tion,the engagement of the ratchet face 47 of the clutch base 46 with the ratchet face 48 of the idle gear 22, will lock said idle gear. Inasmuch as the rotation of the feed gear 21,-which, as explained, both itself and through its sleeve 44, is in threaded engagement with the threads upon the drill,'- will thus be stopped, the rotation. of the drill spindle will also be stopped. The driven gear 38, which is in engagement with the driving gear 27, is formed with an upwardly extending sleeve 39, within which is a. feather 4L0 engaged within a feather-way 41 formed in it and also in the threads of the drill spindle, in such manner that the drill spindle 7, while capable of an up and down movement, will constantly rotate with the driven gear 38 when the latter is rotating. The tubular upper portion of the casing 1, which in this construction is hollow to receive the upper end of the drill spindle 7,

is externally threaded to receive an internally threaded tubular cap 12 which carries] the pyramidal tip 11 on the hand wheel 49. By means of this hand wheel, the casing can be rotated relatively to the drill spindle for the returning of the latter to its original position after the work of drilling has been performed.

In the general operation of this modified construction,'after the tool has been connected with the drill spindle and the gears 22 and 27 clutched,as the gear spindle revolves, the gear 38 being feathered upon said spindle, will transmit motion to, the gear 27, which, in turn, being in mesh with the gear 22, will drive the gear 21 which, operating upon the threads upon the drill spindle, will cause the forward feed of thedrill. In the return of the spindle to its original position, partly already explained, the

stem 23 must, first, be raised until the ratchet faces l7 and 48 are in contact so as to lock the gear and prevent it and the gear 27 from turning;then, as the drill spindle revolves, it will screw up through the threaded sleeve l4 on the gear 21, and, the gear stem remaining raised, the machine may be fed by hand by the hand wheel 49. In this construction, the same numerical differentiation between the teeth of the en gaged gears and the threads per inch of the drill spindle and feed gear 21, as in the consented in Figs. 3 and 4, in which I have represented a plurality of two sets or units of pairs of feed gears, and a convenient means for engaging and disengaging them by pairs,the offset 2A of the casing 1 is essentially triangular, being adapted to inclose either a feed screw and drill spindle of the construction of Fig. 1, or a drill spindle of the construction of Fig. 2, and also the gears 22 and 27 which are directly connected with or encompass said drilling elements. In addition to these gears 22 and 27 which are provided with the clutch faces 36 and 37 as in the constructions referred to, and mounted upon a gear stem 23 similar to that in said constructions, I have added an additional pair of gears, 50 being an idle gear,

' and 51 being a driving gear, and which are respectively provided with clutch faces 52 and 53 and respectively mounted upon a gear stem 54 correspondent to the gear stem 23. In this construction, the difierence between the pair of gears designated 22 and 27 and the pair designated 50 "and 51, is only either in their relative diameters or in the relative numerical differentiation of their teeth,their relative cooperation with the feed gear 21 and the driven gear 38 of the constructions of Figs. 1 and 2 being the same, and the purpose of their employment being solely to increasethe feed possibilities of the drill. In order to engage or disengage these. pairs of gears, so as to throw either pair into mesh with the gears of the drilling member, that is the feed screw or the drill spindle, I provide a rocker arm 55 fulcrumed at 56, and, as a convenient means ofconnection, externally fork or bifurcate it at both ends, as at 57 and 58, so that the forks may be engaged with circular channels 59 and 60 respectively formed in the gear stems 54 and 23. The throwing in or out of these pairs of gears is eflected through the rocker arm, by the depression of the heads or push buttons 30 upon one or the other of the gear stems 54 or 23.

It will be apparent that the gear 61 seen in Fig. 3 may correspond to either of the gears 21 seen in Figs. 1 or 2, and as the general construction, manner of assembling, and

mode of operation will be apparent from the foregoing description of Figs. 1 and 2, I have deemed it unnecessary to repeat the same in detail.

It will be apparent that the drill spindle 7 in all the embodiments of my invention may be rotated by any suitable medium, as my invention in its broad aspects is applicable to either a rotary piston drill or a reciprocating piston drill, or the rotation of the drill. spindle may be effected by electricity or any other source of power.

It will now be apparent that I have devised a novel and useful construction of an automatic portable feed for drills which embodies the features of. advantage enumerated as desirable in the statement of the invention and the above description, and that while I have in the present instance shown and described preferred embodiments which will be found in practice to give satisfactory results, it is to be understood that they are susceptible of modification in various particulars without departing from the spirit or scope of the invention or sacrificing any of its advantages.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is r 1. A portable drill, comprising in combination a drill-carrying member, means for rotating the same, manually-actuated supplemental gearing one member of which is rotatable with said member for controlling the feed of the drill-carrying member, and means in addition to said supplemental gearing for locking the latter in predetermined positions.

2. A portable drill, comprising in combination, a rotatable drill-carrying member, gearing operatively connected therewith to occasion the rotative advance of said member, manually-actuated supplemental gearing one member of which is rotatable withsaid drill-carrying member for controlling said first-mentioned gearing, and means for automatically locking said supplemental gearing in predetermined positions said locking means being in addition to said gearing.

3. A portable drill, comprising in combination, a rotatable drill-carrying member, gearing operatively connected therewith to occasion the rotative advance of said member, manually-actuated supplemental gearing one member of which is rotatable with said drill-carrying member for controlling said first-mentioned gearing, and means for automatically locking said supplemental gearing in predetermined positions, the driving gear embodying feed and idle gears with a different number of teeth.

4:. In a portable drill, a casing, a threaded drill-carrying member rotatable in bearings within the casing and the drill-carrying end'of which extends beyond said casing, means for occasioning the rotation of said member, manually actuated supplemental controlling means including a gear carried by said member and an idle gear for cooperation therewith for controlling the feed of said member, and means independent of and constructed for automatically locking said controlling means.

5. A portable drill, comprising in combination, a drilling bit, a rotatable externally-threaded feed screw for carrying said bit, a rotatable internally-threaded drill spindle within which said feed screw is mounted, a feed gear keyed to the drill spindle, anidle gear meshed with said feed gear, a driving gear adapted to be engaged With and disengaged from said idle gear, a driven gear meshed with said driving gear and in splined engagement with the feed screw, means for engaging and disengaging the idle gear and the driving gear, and means for locking in a desired position the engaging and disengaging means.

6. A portable drill, comprising in combination, a, drilling bit, a rotatable exter-v nally-threaded feed screw for carrying said bit, a rotatable internally-threaded drill spindle within which said feed screw is mounted for longitudinal traverse, a feed gear keyed to the drill spindle, an idle gear meshed with said feed gear and having an external clutch face, a driving gear adapted to be engaged with and disengaged from said idle gear and having an oppositely correspondent external clutch face, a riven gear meshed with saiddriving gear and in splined engagement with the feed screw,

and means for engaging and disengaging the I idle gear and the driving gear.

7. A portable drill, comprising in combination, a drilling bit, a rotatable externallythreaded feed screw for carrying said bit,

a rotatable internally-threaded drill spindle 1 within which said feed screw is mounted for longitudinal traverse, a feed gear keyed to the drill spindle, an idle gear meshed with said feed gear and having an externalclutch face, a driving gear adapted to be engaged ,with and disengaged from said idle gear 85 and having an oppositely correspondent external clutch face, a driven gear meshed with said driving gear and in splined engagement with the feed screw, and a gear stem common to both the idle gear and the driving gear J which operates to effect their engagement or V disengagement.

8. A portable drill, comprising in combination, a drilling bit, a rotatable externallythreaded feed screw for carrying said bit, a

rotatable internally-threaded drill spindle withinwhich said feed screw is mounted for longitudinal traverse, a feed gear keyed to the drill spindle, an idle gear meshed with said feed gear and having an external clutchface, a driving gear adapted to be engaged with and disengaged from said idle gear and clutch face, a driven gear meshed with said havmg an oppositely correspondent external driving gear and in splined engagement with the feed screw, a gear stem common to both the idle gear and the drivinggear which operates to efiect their engagement or dis- I engagement, and an automatic locking device to retaln the gear stem in different predetermined positions.

9. A portable drill, comprising in combination, a casing, a threaded drill-carrying member housed and rotatable within said. casing and the drill-carrying end of which extends beyond said casing, means'for conengaging means.

tinuous'ly rotating said drill-carrying member, supplemental controlling means for both starting and stopping the rotation of said member, and means for locking said controlllng means n desired positions.

' 10. A portable drill, comprising in com-' 'bination, a threaded rotatable drill-carrying member, a feed gear keyed to said member, an idle gear engaging with said feed gear, a driving gear adapted to be engaged with and disengaged from said idle gear, a driven gear, means for engaging and disengaging the idle gear and the driving gear, and means for locking sald engaging and dls- 11. A device of the character stated, com-" prising a casing,a threaded drill-carrying member rotatable in bearings within the casing,means for occasioning the continuous rotation of said member,a manuallyactuated supplemental controlling gearing which consists of a feed gear, an idle gear rotatable with said member, a driving gear, anda driven gear, all of which gears coact to start and stop the rotation of said drill-, carrying member, said idle and. driving gears being respectively provided with oppositely counterpart clutching faces,and a means for locking said controlling gearing in given positions.

I p 12. A device of the character stated, comprising, a casing,a threaded drill-carrying terpart clutching. faces, and a driven gear,

which together coact to start and stop the rotation of said drill-carrying member.

13. A device of the character stated, comprising, a casing,a threaded drill-carrying member rotatable in-bearings within the casing,means for occasioning the continuous rotation of said member,-and"a manuallyactuated supplemental controlling gearing which consists of a feed gear, an idle gear rotatable with said member, a driving gear, andv a driven gear, the teeth of the feed gear and idle gear corresponding insize to but differing numerically from the teeth of the driving gear and driven gear, all of which gears coact tostart and stop the rotation of said drill-carrying member, and means for locking said supplemental controlling gearing.

14. A device ofthe character stated,,comprising, a casing,a threaded drill carrying member rotatable in bearings Within the the casing,means for occasioning the continuous rotation of said member,.and a manually-actuated supplemental controlling idle gear, a driving gear,said idle gear and driving gear being respectively provided with oppositely counter-part clutching fac'es, anda driven gear, the teeth of i the feed gear and idle gear corresponding in size to but diilering numerically from the teeth of the driving gear and 'driven gear and stop the rotation of said drill-carrying member.

and all of the gears coacting to start 15. A portable drill, comprising in combination, a drilling bit, a rotatable externallythreaded feed screw,a rotatable internallythreaded drill spindle. within which said feed screw is mounted, manually-actuated supplemental controlling gearing which consists of'a feed gear keyed to the drill spindle, an idle gear meshed with said feed gear, a' driving gear adapted to be engaged with and disengaged from said idle gear, and a driven gear meshed with said driving gear and in splined engagement] with the feed screw, all of said gears coacting to stop and start the rotation of the feed screw and drill spindle, and means for locking said supplemental controlling gearing.

' 16. A portable drill, comprising in combination, a drilling bit, a rotatable externally-threaded feed screw for carrying said bit, a rotatable internallythreaded drill spindle within which said feed screw is mounted, and manually-actuated supplemental controlling gearing which consists of a feed gear keyed tothe drill spindle, an idle gear meshed with said feed gear, a driving gear adapted to be engaged with and disengaged from said idle gear, and a driven gear meshed with said driving gear and in 'splined engagement with the feed screw, the teeth of the feed gear and idle gear corresponding in size to but diflering numerically from the teeth of the driving gear and the driven gear, and all of said gears coacting i to stop and start therotation oi. the feed screw and drill spindle.

17". A portable drill, comprising in comf bination, a drilling bit, a rotatable externally-threaded feed screw for carrying said bit, a I rotatable internally -.thre'aded drill 5V spindle within which said feed screw is mounted, and manuallyactuated supplemental controlling gearing which consists of a feedgear keyed to the drill spindle, an idle gear meshed with said feed gear, a driving gear adapted to. be engaged with and disen a ed from said'idle eal. said idle b. a z: a

gear and driving gear being respectively provided. with oppositely counterpart clutching faces, and a driven ear meshed with said driving'gear and in'sgl'ined engagement "withcthe feed screw,.the teeth ofjthe feed gear and idle gear corresponding in size 'to but dlffering numerically from the teeth of the driving gear andthe driven gear, and

1 all of said gears coacting to stop and start the rotation of the feed screw and drill spindle, means for engaging and disengaging the clutching faces of the idle gear and the driving gear, and means for locking said engaging and disengaging means.

18. A portable drill, comprising in combination, a threaded drill-carrying member rotatable in bearings within a casing, a feed gear and a driven gear upon said member, and a manually-actuated supplemental controlling gear which comprises a plurality of units, each of which units consists of an idle gear and a driving gear respectively controlled by a common operating means, and which are relatively and by units respectively engaged with the feed gear and driven gear of the drill-carryingmember.

' 19. A portable drill, comprising in combination, a threaded rotatable drill-carrying member, afeed' gear keyed to said member, an idle gear engaging said feed gear, a driving gearadapted to be. engaged with and disengaged from said. idle gear, a driven gear providedwith a thumb sleeve embrac ing the threaded rotatable drill-carrying member, and means for engaging and disengagingthe' idle gear and the driving gear.

20-. A portable drill, comprising in combinati'on, a threaded rotatable drill-carrying member, a feed gear keyed to said member, an idle gear enga ing said feed gear, a drivgear adapted to. be engaged with and disengaged from said idle gear, a driven, gear provided with a thumb sleeve embracing the threaded rotatable drill-carrying memher, a gear stem common to both the idle gear and the driving gear and which operates to effect their engagement or disengagement, and an automatic locking device to retain the gear stem in different" predetermined positions. I

21. A portable drill, comprising in combination, a threaded rotatable drill-carrying an idle gear engaging with said feed gear, a

drivinggear adapted to be engaged: with and disengaged from said idle gear, a driven gear, a ear stem common to both the idle gear and thedriving gear and which operates toeii'ect their engagement or disengagement, andan automatic locking device to retain the gear stem in different predetermined positions. i

22. A portabl drill, comprising in combination, a threaded rotatable drill-carrying member, a feed gear keyed to said member, an idle gear engaging-avith said feed gear and having a ratcheted under face, a drivinggear adapted to bejenga-ged with and disengaged from said idle gear, a driven gear, 'a gear stem common to'both the idle gagement and which is formed with a both the idle gear and the driving gear and which operates to effect their engagement 15 and disengagement and which is formed With a ratcheted clutch face adapted to engage the ratchet face of the idle gear, and an automatic locking device to retain the gear stem in different predetermlned posi- 2O tions.

EDWARD H. CHAPMAN.

WVitnesses MAURICE ASHER, EUGENE ESSNER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

